MELBOURNE — Victoria Azarenka had the bulk of the crowd against her. The fireworks were fizzling out, and when she looked over the net, she saw Li Na crashing to the court and almost knocking herself out.

Considering the cascading criticism she'd encountered after her previous win, Azarenka didn’t need the focus of the Australian Open final to be on another medical timeout.

So after defending her title with a 4-6, 6-4, 6-3 victory over the sixth-seeded Li in one of the most unusual finals ever at Melbourne Park, Azarenka understandably dropped her racket and cried tears of relief late Saturday night.

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She heaved as she sobbed into a towel beside the court, before regaining her composure to collect the trophy.

‘‘It isn’t easy, that’s for sure, but I knew what I had to do,’’ the 23-year-old Belarussian said. ‘‘I had to stay calm. I had to stay positive. I just had to deal with the things that came onto me.’’

There were a lot of those things squeezed into the 2-hour-40-minute match. Li, who was playing her second Australian Open final in three years, twisted her ankle and tumbled to the court in the second and third sets.

The second time was on the point immediately after a 10-minute delay for the Australia Day fireworks — a fixture in downtown Melbourne every Jan. 26, but not usually coinciding with a final.

Li had been sitting in her chair during the break, while Azarenka jogged and swung her racket before leaving the court to rub some liniment into her legs.

The 30-year-old Chinese player had tumbled to the court after twisting her left ankle and had it taped after falling in the fifth game of the second set. Immediately after the fireworks ceased, and with smoke still in the air, she twisted the ankle again, fell and hit the back of her head on the hardcourt.

The 2011 French Open champion was treated immediately by a tournament doctor and assessed for a concussion in another medical timeout before resuming the match.

‘‘I think I was a little bit worried when I was falling,’’ Li said, in her humorous, self-deprecating fashion. ‘‘Because two seconds I couldn’t really see anything. It was totally black.

‘‘So when the physio come, she was like, ‘Focus on my finger.’ I was laughing. I was thinking, ‘This is tennis court, not like hospital.’ ’’

Li’s injury attracted even more support for her from the 15,000-strong crowd.

Azarenka had generated some bad PR by taking a medical timeout after wasting five match points on her own serve in her semifinal win over American teenager Sloane Stephens Thursday. She came back after the break and finished off Stephens in the next game, later telling an on-court interviewer that she ‘‘almost did the choke of the year.’’

She was accused of gamesmanship and manipulating the rules to get time to regain her composure against Stephens, but defended herself by saying she actually was having difficulty breathing because of a rib injury that needed to be fixed.

That explanation didn’t convince everybody. So when she walked onto Rod Laver Arena Saturday, there were some people who booed, and others who heckled her or mimicked the distinctive hooting sound she makes when she hits the ball.

‘‘Unfortunately, you have to go through some rough patches to achieve great things,’’ she said. ‘‘That’s what makes it so special for me. I went through that, and I'm still able to kiss that beautiful trophy.’’

She didn’t hold a grudge.

‘‘I was expecting way worse, to be honest,” she said. “What can you do? You just have to go out there and try to play tennis in the end of the day,’’ she said. ‘‘It’s a tennis match, tennis battle, final of the Australian Open. I was there to play that.

‘‘The things what happened in the past, I did the best thing I could to explain, and it was left behind me already.’’

The match contained plenty of nervy moments and tension, and 16 service breaks — nine for Li. But it also produced plenty of winners and bravery on big points.

Azarenka will retain the No. 1 ranking she has mostly held since her first Grand Slam win in Melbourne last year.

Li moved into the top five and is heartened by a recent trend of Australian runner-ups winning the French Open. She accomplished that in 2011, as did Ana Ivanovic (2008) and Maria Sharapova (2012).

Later Saturday, Bob and Mike Bryan won their record 13th Grand Slam men’s doubles title, defeating the Dutch team of Robin Haase and Igor Sijsling, 6-3, 6-4.

Sunday’s men’s final features two-time defending champion Novak Djokovic and US Open winner Andy Murray. Djokovic is seeking to become the first man in the Open era to win three titles in a row in Australia.